Technology

Digital camera An overview of digital cameras: how they work, main components and types, brief history, common uses, and key differences from film cameras.

Public-key digital certificates: identity credentials, X.509 format, and lifecycle Digital certificates Overview of public-key digital certificates: how X.509 credentials bind identities to public keys, CA issuance, usage in TLS and digital signatures, certificate formats, revocation…

Digital Compact Cassette (DCC): a consumer digital tape format Digital Compact Cassette Digital Compact Cassette (DCC) was a magnetic tape format developed by Philips in the early 1990s to offer digital recording in a cassette-compatible shell. It competed with MiniDi…

Digital electronics: principles, components, history and applications Digital electronics An overview of digital electronics covering core concepts, typical components, historical development, common applications (computers, phones, cameras) and distinctions from analog…

Digital Enhanced Cordless Telecommunications (DECT) Digital Enhanced Cordless Telecommunications DECT is a standardized digital wireless technology for cordless voice and data links, widely used for home and business phones, offering secure, low-interference communication and…

Digital Light Processing (DLP): Technology, Uses, and History Digital light processing Digital Light Processing (DLP) is a light-modulation technology using micromirrors for projection and photopolymer curing; used in cinema, business projectors, pico devices and som…

Digital Object Identifier (DOI): persistent identifiers for digital content Digital Object Identifier A Digital Object Identifier (DOI) is a persistent, actionable identifier for electronic documents and other digital objects, used widely in scholarly publishing, data citation, and…

Digital pet (virtual pet) Digital pet An overview of digital pets: software-based companions that simulate animals, their history, typical features, common uses, and how they differ from real pets and other virtual cre…

Digital rights management (DRM): overview, mechanisms, uses and controversies Digital rights management Digital rights management (DRM) comprises technologies and policies that control access, copying, and redistribution of digital content. This article explains how DRM works, its hi…

Digital Signal Controller A Digital Signal Controller (DSC) is a hybrid embedded processor that combines features of microcontrollers and digital signal processors for real-time control and signal processin…

Digital Signal Processor (DSP): Specialized Microprocessors for Real-Time Signal Processing Digital signal processor A digital signal processor (DSP) is a microprocessor optimized to perform high-speed numerical operations on sampled signals for audio, communications, control and other real‑time…

Digital signature: purpose, operation, uses and legal context Digital signature A digital signature is a cryptographic construct that authenticates digital data, ensures integrity and supports non‑repudiation. Used in code signing, secure email, documents and…

Digital Visual Interface (DVI): digital video connector and standards overview Digital Visual Interface DVI is a video connector and signaling specification for carrying uncompressed digital (and optionally analog) video between sources and displays. It enabled digital desktop displa…

Digital-to-Analog Converter (DAC): Principles, Types, and Applications Digital-to-analog converter An overview of digital-to-analog converters: what they are, main architectures, performance measures, historical development, and common applications such as audio, instrumentation…

DIN connector: round multi‑pin electrical connectors, types and uses DIN connector Overview of DIN connectors: origin, common pin layouts, typical uses (audio, MIDI, keyboards), mini‑DIN variants, advantages and limitations, and historical development.

Diode — two-terminal semiconductor device Diode A diode is a two-terminal electronic device that conducts primarily one way. Common semiconductor diodes are used for rectification, signal detection, voltage reference, switching…

DIP switch (dual in-line package switch) DIP switch A DIP switch is a small manually operated set of electrical switches packaged like an integrated circuit. Used for hardware configuration, addressing, and low-voltage signal select…

Dipole antenna A dipole antenna is a fundamental radio antenna made of two conductive elements, typically about half a wavelength long. It serves as a simple, efficient driven element in many ant…

Dipstick (measuring rod and test strip) Dipstick A dipstick is a simple tool dipped into a liquid to indicate level or detect substances. Common in engines, tanks and medical tests, it remains a low‑cost, direct method alongside…

Direct memory access (DMA): overview, operation, uses and considerations Direct memory access Direct memory access (DMA) lets hardware transfer data to or from main memory without continuous CPU intervention, improving throughput for I/O and multimedia tasks while introduci…

DirectX: Microsoft's multimedia and gaming application programming interfaces DirectX DirectX is a collection of Microsoft APIs that provide hardware-accelerated graphics, audio, input and networking services for games and multimedia on Windows and Xbox platforms.

Dirty bomb (radiological dispersal device) Dirty bomb An overview of dirty bombs (radiological dispersal devices): how they work, likely effects, history, prevention and how they differ from nuclear weapons.

Disc-detainer lock (disc-tumbler / Abloy style) — mechanism and uses Disc-detainer lock A disc-detainer (disc-tumbler or Abloy) is a key-operated high-security lock that uses rotating discs. This article explains its mechanism, history, uses, advantages, and notable d…

Discogs: community-built music database and marketplace Discogs Discogs is a crowd-sourced music database and marketplace primarily known for detailed release data, vinyl and electronic music coverage, and tools for collectors and researchers.

Dishwasher (machine and occupation) Dishwasher Overview of dishwashers: the appliance that cleans tableware and the person who performs that task. Covers operation, main parts, history, types, uses, maintenance and safety consi…

Disk buffer: onboard memory in hard disk drives Disk buffer Overview of the disk buffer (on-drive DRAM): its role, typical sizes, behavior, differences from operating-system caches, performance effects, and reliability considerations.

Disk image A disk image is a single file that contains a sector-by-sector copy of a storage device, including files, file system metadata, boot records and partition tables; used for backup,…

Disk partitioning: concepts, schemes, uses and best practices Disk partitioning Overview of disk partitioning: what partitions are, common schemes (MBR/GPT), typical uses (OS separation, swap, multi‑boot), risks and practical recommendations for managing parti…

Disruptive innovation Disruptive innovation: the process by which simpler, cheaper, or more convenient offerings create new markets and eventually displace incumbent products or firms.

Distributed computing: principles, models, and applications Distributed computing Overview of distributed computing: definitions, architectures, history, common models (clusters, grids, cloud, peer-to-peer), key challenges (consistency, fault tolerance) and typi…

Dither (noise techniques to reduce quantization error) Dither Dither is the deliberate addition or manipulation of noise to reduce artifacts from quantization or limited palettes in images, audio, and printing, improving perceived fidelity.

Diving bell A diving bell is an early, simple underwater chamber that traps air beneath the surface. It remains in use for salvage, construction and as transfer chambers in commercial diving d…

DjVu — a compressed file format optimized for scanned documents DjVu DjVu is a file format and set of tools for efficiently storing and distributing scanned pages that combine text, line art and photographs, often producing smaller files than scanne…

DK Bongos: The Donkey Kong Bongo Controller for GameCube DK Bongos A bongo-shaped percussion controller for Nintendo GameCube, introduced with Donkey Konga and later used in other Donkey Kong titles and Super Smash Bros. Uses two drum pads and a c…

Döbereiner's Lamp: an early hydrogen lighter and catalytic ignition device Döbereiner's lamp Döbereiner's lamp, invented by Johann Wolfgang Döbereiner in 1823, produced a flame by generating hydrogen and igniting it catalytically on platinum. Design, chemistry, operation,…

Document Object Model (DOM): structure, API, history, and usage Document Object Model The Document Object Model (DOM) is a standardized, language-neutral interface that represents HTML and XML documents as a tree of nodes, enabling scripts and programs to inspect an…

Documentation: purpose, types, structure, and best practices Documentation A concise guide to documentation: what it is, common formats and components, historical development, practical uses, and guidelines for clear, maintainable documentation.

Donkey Kong (Game Boy) — handheld platform reinterpretation Donkey Kong (handheld game) A portable reinterpretation of the arcade classic for Nintendo's Game Boy. Blends faithful early stages with new levels and puzzle-platform elements starring Mario and Donkey Kong.

Donkey Kong (1981 video game) Donkey Kong (video game) Donkey Kong is a 1981 arcade platform game by Nintendo that introduced Mario and established early platforming conventions. It features climbing-based stages, hazardous obstacles,…

Donkey Kong 3: 1984 Nintendo arcade shooter Donkey Kong 3 Donkey Kong 3 (1984) — Nintendo arcade shooter in which a pesticide specialist protects a greenhouse from Donkey Kong and insects; overview of gameplay, ports (NES, Virtual Console…

Donkey Kong Barrel Blast Donkey Kong Barrel Blast is a 2007 racing video game for the Wii featuring franchise characters, motion-based controls and both single-player and local multiplayer modes; it had a…

Donkey Kong Country (1994 video game) Donkey Kong Country 1994 platformer developed by Rare for the Super Nintendo. Noted for pre-rendered 3D visuals, memorable soundtrack and enduring influence; spawned sequels, remakes and many re-relea…

Donkey Kong Jungle Beat A rhythm-infused platform game for Nintendo GameCube that uses the DK Bongos controller; notable for score-driven levels, unique input, and a later Wii re-release with traditional…

Donkey Kong Land A 1995 Game Boy platformer developed by Rare that adapts the Donkey Kong Country style for handheld play; features Donkey Kong and Diddy Kong in original levels evoking the SNES pr…

Doom engine (id Tech 1) — architecture, history, and legacy Doom engine Software engine that powered Doom and related games; a landmark 2.5D, software-rendered engine known for its BSP-based architecture, WAD data format, moddability and widespread por…

Doorbell A doorbell is a signaling device mounted by an entrance that notifies occupants of a visitor. Variants include mechanical, electric, wireless, and smart video doorbells used in hom…

Doping (semiconductor materials) Doping (semiconductor) Intentional introduction of impurities into semiconductors to control electrical behavior. Explains n‑ and p‑type mechanisms, methods such as diffusion and ion implantation, histor…

Disk Operating System (DOS): Overview, History, and Uses DOS An accessible overview of disk operating systems (DOS): what they are, how they work, their history including MS‑DOS and QDOS, common commands and file systems, legacy uses and not…